modelLocalPipeFlowHeatTransfer
LocalPipeFlowHeatTransfer: Laminar and turbulent forced convection in pipes, local coefficients
Extends from TRANSFORM.Fluid.Pipes_Obsolete.ClosureModels.HeatTransfer.Models.PartialHeatTransfer_setQ_flows (Base model required to allow for models that set Q_flows state rather than temperature state).
Information
Heat transfer model for laminar and turbulent flow in pipes. Range of validity:
- fully developed pipe flow
- forced convection
- one phase Newtonian fluid
- (spatial) constant wall temperature in the laminar region
- 0 ≤ Re ≤ 1e6, 0.6 ≤ Pr ≤ 100, d/L ≤ 1
- The correlation holds for non-circular pipes only in the turbulent region. Use diameter=4*crossArea/perimeter as characteristic length.
The correlation takes into account the spatial position along the pipe flow, which changes discontinuously at flow reversal. However, the heat transfer coefficient itself is continuous around zero flow rate, but not its derivative.
References
- Verein Deutscher Ingenieure (1997):
- VDI Wärmeatlas. Springer Verlag, Ed. 8, 1997.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Acceleration | g (from PartialHeatTransfer_setT) | Modelica.Constants.g_n | Gravitational acceleration |
| Internal Interface › Geometry | |||
| Real | nParallel (from PartialHeatTransfer_setT) | Number of parallel heat transfer segments | |
| Integer | nHT (from PartialHeatTransfer_setT) | geometry.nNodes | Number of serial heat transfer segments |
| Internal Interface › Inputs | |||
| Boolean | use_Dimensions (from PartialHeatTransfer_setT) | geometry.use_Dimensions | = true to specify characteristic dimension |
| Internal Interface › Nominal Conditions: | |||
| SI.MassFlowRate | m_flow_nominal (from PartialHeatTransfer_setT) | 1 | Mass flow rate |
| SI.Pressure | p_nominal (from PartialHeatTransfer_setT) | Medium.p_default | Pressure |
| Boolean | use_T_nominal (from PartialHeatTransfer_setT) | true | = true then use temperature else enthalpy |
| SI.Temperature | T_nominal (from PartialHeatTransfer_setT) | if use_T_nominal then Medium.T_default else Medium.temperature_phX(p_nominal, h_nominal, X_nominal) | Temperature |
| SI.SpecificEnthalpy | h_nominal (from PartialHeatTransfer_setT) | if use_T_nominal then Medium.specificEnthalpy_pTX(p_nominal, T_nominal, X_nominal) else Medium.h_default | Specific Enthalpy |
| Medium.MassFraction[Medium.nX] | X_nominal (from PartialHeatTransfer_setT) | Medium.X_default | Mass fractions m_i/m |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| HeatAndMassTransfer.Interfaces.HeatPort_Flow | heatPorts (from PartialHeatTransfer_setT) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | states (from PartialHeatTransfer_setT) | Thermodynamic state of fluid | |
| SI.MassFlowRate | m_flows (from PartialHeatTransfer_setT) | Mass flow rate | |
| Geometry | geometry (from PartialHeatTransfer_setT) | ||
| SI.Length | lengths (from PartialHeatTransfer_setT) | geometry.dlengths | Characteristic length of heat transfer segment |
| SI.Diameter | dimensions (from PartialHeatTransfer_setT) | geometry.dimensions | Characteristic dimension (e.g. hydraulic diameter) |
| SI.Area | crossAreas (from PartialHeatTransfer_setT) | geometry.crossAreas | Cross sectional area |
| SI.Length | perimeters (from PartialHeatTransfer_setT) | geometry.perimeters | Wetted perimeter |
| SI.Area | surfaceAreas (from PartialHeatTransfer_setT) | geometry.surfaceAreas_23 | Heat transfer area |
| SI.Temperature | Ts_fluid (from PartialHeatTransfer_setT) | Medium.temperature(states) | Fluid temperature |
| SI.Temperature | Ts_wall (from PartialHeatTransfer_setT) | heatPorts.T | Wall temperature |
| SI.Temperature | Ts_film (from PartialHeatTransfer_setT) | 0.5*(Ts_wall + Ts_fluid) | Film temperature |
| Medium.ThermodynamicState | states_film (from PartialHeatTransfer_setT) | Medium.setState_pTX(states.p, Ts_film, Medium.X_default) | Film state |
| SI.CoefficientOfHeatTransfer | alphas (from PartialHeatTransfer_setT) | Coefficient of heat transfer | |
| SI.HeatFlowRate | Q_flows (from PartialHeatTransfer_setT) | heatPorts.Q_flow | Heat flow rate |
| Media.BaseProperties1Phase | mediums1 (from PartialHeatTransfer_setT) | Bulk fluid properties | |
| Media.BaseProperties1Phase | mediums1_film (from PartialHeatTransfer_setT) | Film fluid properties | |
| SI.NusseltNumber | Nus | Nusselt number | |
| SI.ReynoldsNumber | Res | Reynolds number | |
| SI.PrandtlNumber | Prs | Prandtl number |